Fixing device and image forming apparatus

Abstract

To prevent the occurrence of printing failure.SOLUTION: A fixing device comprises: a fixing member that has a lubricant on its inner peripheral surface, and is rotatable in a longitudinal direction as a rotation axis direction; slide rings that are arranged opposite to the side ends in the longitudinal direction of the fixing member; a pressure member that is provided opposite to an outer peripheral surface of the fixing member, and is in contact with the outer peripheral surface of the fixing member to form a nip part with the fixing member; and contact members that are arranged on the side ends in the longitudinal direction of the pressure member, and are in contact with the slide rings.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a fixing device and an image forming apparatus. [Background technology]

[0002] In an electrophotographic image forming apparatus, an image (also called a developer image) formed using a developer such as toner is transferred onto a medium such as paper, and then the image (developer image) transferred onto the medium is fixed to the medium by a fixing device that serves as a fixing apparatus.

[0003] This fixing device rotates a cylindrical fixing member formed by a roller or belt etc. and a cylindrical pressure member formed by a roller or belt etc. while they are in contact with each other, and heats and presses the medium while sandwiching it in the nip area formed between the fixing member and the pressure member and transporting it, thereby heating and melting the image (developer image) formed on the medium and fixing it onto the medium.

[0004] In a conventional fixing device, a contact member that contacts the inner peripheral surface of the fixing member is provided on the inner peripheral side of the fixing member, and the fixing member rotates while sliding against the contact member, so a lubricant such as grease is applied between the fixing member and the contact member. The contact member is, for example, a heat diffusion member that transfers heat from a heater to the fixing member, or a guide member that guides the fixing member (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-3642 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in conventional fixing devices, lubricant could leak from the end of the fixing member in the direction of the rotation axis, and if the leaked lubricant adheres to the outer peripheral surface of the fixing member, heat cannot be transferred sufficiently when fixing an image onto the media, which can result in printing defects.

[0007] The present invention has been made in consideration of the above points, and aims to propose a fixing device and an image forming apparatus that are capable of suppressing the occurrence of printing defects. [Means for solving the problem]

[0008] The fixing device of the present invention includes a fixing member having a lubricant on its inner surface and rotatable with its axis of rotation in the longitudinal direction, a sliding ring arranged opposite a longitudinal side end of the fixing member, a pressure member arranged opposite an outer peripheral surface of the fixing member and abutting against the outer peripheral surface of the fixing member to form a nip portion between the fixing member and the pressure member, and a contact member arranged at a longitudinal side end of the pressure member and in contact with the sliding ring.

[0009] The image forming apparatus of the present invention includes the fixing device described above.

[0010] In the fixing device of the present invention, lubricant leaking from the end of the fixing member adheres to the sliding ring, but the lubricant adhering to the sliding ring can be removed by a contact member that comes into contact with the sliding ring, so that the lubricant leaking from the end of the fixing member can be prevented from adhering to the outer peripheral surface of the fixing member via the sliding ring. Effect of the Invention

[0011] According to the present invention, it is possible to realize a fixing device and an image forming apparatus that are capable of suppressing the occurrence of printing defects. [Brief description of the drawings]

[0012] [Figure 1] 1 is a diagram showing a configuration of an image forming apparatus according to an embodiment; [Diagram 2] 2A and 2B are diagrams illustrating an external configuration of a fixing unit according to an embodiment. [Diagram 3] 5A and 5B are diagrams illustrating configurations of a heating unit and a pressure unit according to the embodiment. [Figure 4] FIG. 4 is an enlarged view of a portion of the heating unit in FIG. 3. [Diagram 5] 4 is an enlarged view of a portion of the heating unit in FIG. 3 (a portion different from that in FIG. 4). [Figure 6] 5A and 5B are diagrams illustrating a configuration of a heating unit according to an embodiment. [Figure 7] FIG. 4 is a diagram showing a portion of a heating unit and a pressure unit according to an embodiment. [Figure 8] 1A and 1B are diagrams illustrating a configuration of a circular belt according to an embodiment. [Figure 9] 1A and 1B are diagrams showing a configuration of a support according to an embodiment. [Figure 10] 1A and 1B are diagrams illustrating a configuration of a sliding ring according to an embodiment. [Figure 11] 3A and 3B are diagrams illustrating a configuration of a pressure roller according to an embodiment. [Figure 12] 5A and 5B are diagrams showing a configuration of a lubricant recovery member according to an embodiment. [Figure 13] 5A and 5B are diagrams illustrating the positional relationship between a pressure roller, a sliding ring, and a lubricant recovery member according to the embodiment. [Figure 14] FIG. 13 is a diagram illustrating the movement of a lubricant according to an embodiment. [Figure 15] FIG. 13 is a diagram showing the movement of the lubricant when the lubricant recovery member, which serves as a comparison example, is omitted. [Figure 16] 13A and 13B are diagrams illustrating an example of the configuration of a lubricant recovery member according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, modes for carrying out the invention (hereinafter referred to as embodiments) will be described in detail with reference to the drawings.

[0014] [1. Configuration of image forming device] Fig. 1 shows an example of the configuration of an image forming apparatus 200 according to the first embodiment. Fig. 1 is a side cross-sectional view showing the configuration of the image forming apparatus 200. This image forming apparatus 200 is an apparatus that forms an image on a medium M using toner as a developer, and is a so-called electrophotographic color printer. The type of medium M that can be used with the image forming apparatus 200 is not particularly limited, but may be, for example, one or more types of paper, film, etc.

[0015] The image forming apparatus 200 has a substantially box-shaped housing 1. Here, the right side of the housing 1 in the figure is the front side of the housing 1, the left side of the housing 1 in the figure is the rear side of the housing 1, the front side of the housing 1 in the figure is the left side of the housing 1, and the back side of the housing 1 in the figure is the right side of the housing 1. The direction from the left side of the housing 1 to the right side of the housing 1 in the figure (i.e., the direction from the rear side to the front side of the housing 1) is the positive direction in the X-axis direction, the direction from the front side of the housing 1 to the back side of the housing 1 in the figure (i.e., the direction from the left side to the right side of the housing 1) is the positive direction in the Y-axis direction, and the direction from the bottom side of the housing 1 to the top side of the housing 1 in the figure (i.e., the direction from the bottom side to the top side of the housing 1) is the positive direction in the Z-axis direction.

[0016] Provided inside the device housing 1 are a tray T, a developing unit 10, a transfer unit 20, a fixing unit 30, various rollers, and a switching guide 60. The various rollers include, for example, a pickup roller 41, a paper feed roller 42, a separation roller 43, a registration roller 44, a pressure roller 45, and transport rollers 46 to 53. These various rollers and various rollers described below are cylindrical members extending in the Y-axis direction (left-right direction) and are rotatable about a rotation axis extending in the Y-axis direction.

[0017] The tray T is provided at the bottom of the device housing 1, and for example, a plurality of media M are stored (i.e., accumulated) in a stacked state. A stacker 2 into which the media M on which an image is formed is provided on the top surface of the device housing 1. Inside the device housing 1, transport paths R1 to R4 indicated by dotted arrows in the figure are provided between the tray T and the stacker 2, and along the transport paths R1 to R4, a developing unit 10, a transfer unit 20, a fixing unit 30, various rollers, and a switching guide 60 are provided.

[0018] The image forming apparatus 200 is capable of forming an image on one side (front side) of the medium M by switching the transport direction of the medium M using the switching guide 60, and is also capable of forming images on both sides (front and back sides) of the medium M. In other words, the image forming apparatus 200 has a single-sided printing function and a double-sided printing function.

[0019] In this image forming apparatus 200, the medium M is transported in the transport direction indicated by the arrow H on each of the transport paths R1 to R4 (that is, the direction of the dotted arrow indicating each of the transport paths R1 to R4).

[0020] The transport path R1 is a path for transporting the medium M from the tray T to the developing unit 10 and the transfer unit 20 provided at the top of the device housing 1. The transport path R2 is a path for transporting the medium M from the developing unit 10 and the transfer unit 20 to the fixing unit 30 provided behind them when an image is formed on one side of the medium M. The transport path R3 is a path for transporting the medium M from the fixing unit 30 to the stacker 2. The transport path R4 is a path for transporting (bypassing) the medium M from the fixing unit 30 back to the developing unit 10 and the transfer unit 20 in order to form an image on the back side of the medium M after an image is formed on the front side of the medium M when images are formed on both sides of the medium M.

[0021] [1-1.Developing unit] The developing unit 10 and the transfer unit 20 are disposed facing each other in the vertical direction with the transport path R2 in between. Specifically, the developing unit 10 is disposed on the upper side and the transfer unit 20 is disposed on the lower side with the transport path R2 in between. The developing unit 10 is a unit that performs development using toner. Specifically, the developing unit 10 forms an electrostatic latent image by exposure to light, and develops the electrostatic latent image by adhering toner to the electrostatic latent image using Coulomb force.

[0022] The developing unit 10 has a developing unit 11 that performs a developing process and an exposure unit 12 that performs an exposure process. The developing unit 11 is detachable from the device housing 1 and has a photoconductor drum 13 on which an electrostatic latent image is formed. The photoconductor drum 13 is a cylindrical member extending in the Y-axis direction and is rotatable about a rotation axis extending in the Y-axis direction. The exposure unit 12 is attached to the developing unit 11 and exposes the surface of the photoconductor drum 13 to light to form an electrostatic latent image on the surface. The exposure unit 12 has, for example, a light-emitting diode (LED) element as an exposure means. The developing unit 11 forms a toner image on the surface of the photoconductor drum 13 by attaching toner to the electrostatic latent image formed on the surface of the photoconductor drum 13 and developing the image.

[0023] The developing unit 10 has, for example, four developing processing units 11 (11K, 11Y, 11M, 11C) and four exposure processing units 12 (12K, 12Y, 12M, 12C). The four developing processing units 11K, 11Y, 11M, 11C are arranged in this order, for example, from the upstream side in the transport direction indicated by the arrow H. The four exposure processing units 12K, 12Y, 12M, 12C are also arranged in the same order as the four developing processing units 11K, 11Y, 11M, 11C.

[0024] The four developing units 11K, 11Y, 11M, and 11C have the same configuration, except that they use different types (colors) of toner for the developing process. Specifically, the four developing units 11K, 11Y, 11M, and 11C perform the developing process using black (K) toner, yellow (Y) toner, magenta (M) toner, and cyan (C) toner, respectively.

[0025] [1-2. Transcription unit] The transfer unit 20 is a unit that transfers the toner image developed by the development unit 10 onto the medium M. Specifically, the transfer unit 20 transfers the toner image formed on the surface of the photoconductor drum 13 by the development unit 10 onto the medium M that is transported in the transport direction indicated by the arrow H.

[0026] The transfer unit 20 has a drive roller 21, an idle roller 22, a transfer belt 23, and a transfer roller 24. The drive roller 21 is rotatable by a drive source such as a motor. The idle roller 22 is rotatable in response to the rotation of the drive roller 21. The transfer belt 23 is stretched by the drive roller 21, the idle roller 22, and the transfer roller 24, and is capable of running in response to the rotation of the drive roller 21. The transfer roller 24 is in pressure contact with the photosensitive drum 13 via the transfer belt 23, and when the medium M passes between the photosensitive drum 13 and the transfer belt 23, the medium M is charged to a polarity opposite to that of the toner, thereby transferring the toner image formed on the photosensitive drum 13 to the medium M.

[0027] The transfer unit 20 has, for example, four transfer rollers 24 (24K, 24Y, 24M, and 24C). The four transfer rollers 24K, 24Y, 24M, and 24C are arranged in the same order as the four development processing units 11K, 11Y, 11M, and 11C.

[0028] [1-3. Fuser unit] The fixing unit 30 is a unit that fixes the toner image transferred to the medium M by the transfer unit 20. Specifically, the fixing unit 30 fixes the toner image to the medium M by applying heat and pressure to the medium M to which the toner image has been transferred by the transfer unit 20. The configuration of the fixing unit 30 will be described in detail later.

[0029] [1-4. Various rollers and switching guides] The pickup roller 41 is a roller that sends out the medium M from the tray T along the transport path R1. The paper feed roller 42 is a roller that guides (i.e., feeds) the medium M sent out from the tray T by the pickup roller 41 from the transport path R1 to the transport path R2. The separation roller 43 is a roller that separates the uppermost medium M from the other media M when multiple media M are sent out from the tray T so that only the uppermost medium M is fed.

[0030] The registration roller 44 and the pressure roller 45 are rollers that correct the skew of the medium M while transporting the medium M along the transport path R2. The transport rollers 46-53 are pairs of rollers that face each other across the transport paths R2-R4, respectively, and transport the medium M along the transport paths R2-R4. The transport roller 48 is a roller that discharges the medium M on which the toner image has been fixed to the stacker 2.

[0031] The switching guide 60 is disposed downstream of the fixing unit 30 in the transport direction indicated by the arrow H, and is a guide that switches the transport direction of the medium M depending on the image formation format (double-sided image formation and single-sided image formation). Specifically, when an image is formed on only one side (front side) of the medium M, the switching guide 60 transports the medium M from transport path R2 to transport path R3. On the other hand, when an image is formed on both sides (front and back sides) of the medium M, the switching guide 60 transports the medium M from transport path R2 to transport path R4.

[0032] [2. Configuration of the fixing unit] Here, the configuration of the fixing unit 30 will be described in more detail with reference to Figs. 2 to 7. Fig. 2 is a perspective view showing the external configuration of the fixing unit 30. Fig. 3 is a cross-sectional view showing the configuration of the heating section 120 and the pressure section 130 included in the fixing unit 30, and shows a cross section seen from one end side (left side) in the Y-axis direction. Figs. 4 and 5 are partially enlarged cross-sectional views of a part of Fig. 3. Fig. 6 is a cross-sectional view of the heating section 120, and shows a cross section seen from one end side (lower side) in the Z-axis direction. Fig. 7 is a cross-sectional view of the other end part (right end part) of the heating section 120 and the pressure section 130 in the Y-axis direction, and shows a cross section seen from one end side (front side) in the X-axis direction. As shown in Fig. 1, the fixing unit 30 is slightly inclined so that the front side is positioned lower than the rear side, but for simplicity of explanation, this inclination is omitted in Figs. 2 and onwards.

[0033] 2, the fixing unit 30 has a housing 110 that is long in the Y-axis direction, and has a heating section 120 and a pressure section 130 inside the housing 110. The housing 110 has a connector 140 on one side surface (left side surface) that is one end side in the Y-axis direction.

[0034] [2-1. Heating section] 2, 3, and 6, the heating unit 120 includes, for example, a heater 121, a circular belt 122, a temperature sensor 123, a heat conductive plate 124, a heat diffusion member 125, a lubricant 126, supports 127, 128, 161, and 162, a pair of compression springs 129, and a pair of sliding rings 160. Of these, a unit consisting of the heater 121, the circular belt 122, the temperature sensor 123, the heat conductive plate 124, the heat diffusion member 125, and the supports 127 and 128 is called a heater unit 180. Note that, as will be described in detail later, the circular belt 122 is cylindrical and extends in the Y-axis direction, and the heater 121, the temperature sensor 123, the heat conductive plate 124, the heat diffusion member 125, and the supports 127 and 128 are arranged inside the circular belt 122.

[0035] 2 and 6, the heating unit 120 extends in the Y-axis direction, and each part of the heating unit 120, such as the heater 121, also extends in the Y-axis direction. The pair of compression springs 129 (FIG. 2) is an elastic member that is expandable and contractible in, for example, the Z-axis direction. One of the pair of compression springs 129 is attached, for example, to one end side (left end side) of the housing 110 in the Y-axis direction and one end side (left end side) of the heating unit 120 in the Y-axis direction, and the other is attached, for example, to the other end side (right end side) of the housing 110 in the Y-axis direction and the other end side (right end side) of the heating unit 120 in the Y-axis direction.

[0036] The heating unit 120 is movable in the Z-axis direction and is biased by a pair of compression springs 129 in a direction approaching the pressure unit 130 (specifically, downward), so that the heating unit 120 is pressed against the pressure unit 130 when heating the medium M. As a result, a nip portion 150 is formed between the heating unit 120 and the pressure unit 130 (specifically, between the circular belt 122 and the pressure roller 131), as shown in FIG.

[0037] [2-2. Heater] The heater 121 of the heating section 120 generates heat for heating the circular belt 122. The heater 121 is supplied with power from the outside of the fixing unit 30 via a connector 140. The type of the heater 121 is not particularly limited, but may be, for example, a planar heater.

[0038] [2-3. Circular belt] The circular belt 122 is a generally cylindrical (ring-shaped cross section) belt that is heated by heat generated by the heater 121. As shown in Fig. 3, the circular belt 122 rotates in the belt rotation direction indicated by the arrow D in the figure while being heated by the heater 121.

[0039] Specifically, this circular belt 122 is a laminate in which a base material 201 such as a metal such as stainless steel (SUS) or a heat-resistant resin (polyimide), an elastic layer 202 such as silicone rubber, and a surface layer 203 such as a PFA (tetrafluoroethylene-perfluoroalkylvinylether copolymer) tube are laminated in this order, as shown in the cross section seen from one end side in the longitudinal direction in Fig. 8. The length T2 shown in Fig. 8 is the difference between the outer diameter and the inner diameter of the circular belt 122, i.e., the thickness.

[0040] [2-4. Temperature sensor] The temperature sensor 123 is a sensor that detects the temperature (heating temperature) of the heater 121 located below the temperature sensor 123. Since a heat conductive plate 124 is interposed between the heater 121 and the temperature sensor 123, the temperature sensor 123 detects the temperature of the heater 121 via the heat conductive plate 124.

[0041] [2-5.Heat conductive plate] The thermally conductive plate 124 is disposed between the heater 121 and the temperature sensor 123, and is a plate-like member that conducts heat generated from the heater 121 to the temperature sensor 123. The thermally conductive plate 124 is a metal plate such as stainless steel (SUS), and is in contact with the upper surface of the heater 121 and the lower surface of the temperature sensor 123, respectively.

[0042] [2-6. Heat diffusion materials] The heat diffusion member 125 is disposed between the heater 121 and the circular belt 122, and is a plate-like member that separates the circular belt 122 from the heater 121. The heat diffusion member 125 is in contact with the lower surface of the heater 121 and the inner circumferential surface of the circular belt 122. In other words, the heat diffusion member 125 is in contact with a lower portion (the portion on the pressurizing unit 130 side) of the entire inner circumferential surface of the circular belt 122. In other words, the heater 121 and the pressurizing unit 130 face each other with the heat diffusion member 125 and the circular belt 122 sandwiched therebetween.

[0043] The heat diffusion member 125 is a member having thermal conductivity and is adapted to conduct heat generated from the heater 121 to the circular belt 122. Specifically, the heat diffusion member 125 is, for example, a metal plate such as glass-coated stainless steel (SUS) and has high thermal conductivity. The heat diffusion member 125 functions as a heat diffusion plate that diffuses the heat generated from the heater 121 when the heat is conducted to the circular belt 122. As a result, the heat generated from the heater 121 is dispersed and conducted to the circular belt 122, so that the circular belt 122 is heated uniformly and temperature unevenness is less likely to occur in the circular belt 122.

[0044] [2-7. Lubricants] The lubricant 126 is a liquid lubricant for smoothly sliding the circular belt 122 against the heat diffusion member 125 in a state where the heating unit 120 is pressed against the pressurizing unit 130. The lubricant 126 is interposed between the circular belt 122 and the heat diffusion member 125. Specifically, the lubricant 126 is applied to the lower surface of the heat diffusion member 125 (i.e., the surface that contacts the circular belt 122). The lubricant 126 is supplied to the gap between the circular belt 122 and the heat diffusion member 125 as the circular belt 122 rotates when the image forming apparatus 200 starts printing. As a result, the lubricant 126 reduces the frictional resistance between the circular belt 122 and the heat diffusion member 125 when the circular belt 122 slides against the heat diffusion member 125.

[0045] The lubricant 126 may contain one or more additives in addition to the liquid lubricant oil described above. As shown in Fig. 6, when the lubricant 126 is applied to the heat diffusion member 125, the application area 141 has a length W1 in the Y-axis direction (the longitudinal direction of the heat diffusion member 125, i.e., the left-right direction) which is the width of the medium M, and a length W2 in the X-axis direction (the lateral direction of the heat diffusion member 125, i.e., the front-rear direction) which is the length of the nip portion 150.

[0046] After the lubricant 126 is applied to the application area 141, as shown in FIG. 3, the lubricant 126 moves in the directions indicated by the arrows D1, D2, and D3 as the circular belt 122 rotates in the direction of the arrow D, thereby spreading over the entire inner circumferential surface of the circular belt 122.

[0047] [2-8.Support] 3, support 127 is a member that supports heater 121. Support 128 is a member that holds support 127, and is fixed to housing 110. Supports 127, 128 are each a member that extends in the Y-axis direction and has a substantially U-shaped cross section, and are combined such that support 128 is on the upper side and support 127 is on the lower side to form a rectangular tube shape as a whole.

[0048] The temperature sensor 123 is attached to the support 127. The support 127 has a recess extending in the Y-axis direction on its lower surface facing the circular belt 122, and the heater 121, the heat conductive plate 124, and the heat diffusion member 125 are disposed in the recess. For this reason, as shown in FIG. 4 and FIG. 5, both ends of the support 127 in the X-axis direction (short side direction, front-rear direction) are located outside both ends of the heat diffusion member 125 in the X-axis direction (short side direction, front-rear direction). That is, the lower surfaces of both ends of the support 127 in the X-axis direction abut against the inner circumferential surface of the circular belt 122. Note that, as shown in FIG. 3, the lower surfaces of both ends of the support 127 in the X-axis direction (i.e., the portions abutting against the inner circumferential surface of the circular belt 122) are located upstream and downstream of the nip portion 150 in the belt rotation direction (arrow D direction) of the circular belt 122.

[0049] 3 to 6, the corners between the lower surfaces of both ends of the support 127 in the X-axis direction and both end faces of the support 127 in the X-axis direction are defined as edge portions 151 and 152. Of these, the edge portion 151 is an edge portion located on the upstream side when the circular belt 122 rotates in the belt rotation direction (i.e., the upstream side in the belt rotation direction), and the edge portion 152 is an edge portion located on the downstream side in the belt rotation direction. These edge portions 151 and 152 are provided upright so as to contact the inner circumferential surface of the circular belt 122.

[0050] 6 and 7, the supports 161 and 162 are flange-shaped members that support the circular belt 122, and are provided at both ends in the Y-axis direction (longitudinal direction, i.e., left-right direction) of the heating unit 120. In other words, the supports 161 and 162 are provided on one end side and the other end side of the circular belt 122 in the rotation axis direction, and support both ends of the circular belt 122 in the rotation axis direction.

[0051] As shown in Figure 7, the support 161 is provided on the other end side (right end side) of the circular belt 122 in the rotational axis direction (Y axis direction) and is composed of a base 163 facing the belt end surface 122s in the rotational axis direction of the circular belt 122, and a belt insertion portion 164 extending from one surface (the surface facing the belt end surface 122s) 163s of the base 163 toward the circular belt 122 and inserted inside the circular belt 122.

[0052] As shown in FIG. 7 and FIG. 9 showing the support 161 from the Y-axis direction (i.e., the direction of the rotation axis of the circular belt 122), the base 163 is a roughly disk-shaped member whose shape when seen from the Y-axis direction is C-shaped with the opening facing downward, and the longitudinal ends of the supports 127 and 128 are fitted into a recess provided in the center of the lower side.

[0053] The belt insertion portion 164 is a substantially cylindrical member with a part of the outer periphery of a cylinder cut away, and has a C-shape when viewed from the Y-axis direction that is slightly smaller than the base portion 163. The belt insertion portion 164 is provided so as to surround the recess of the base portion 163. The belt insertion portion 164 is inserted into the inside of the other end portion of the circular belt 122 and comes into contact with the inner circumferential surface of the circular belt 122.

[0054] Although omitted in Figure 7, the support body 162 has a configuration similar to that of the support body 161, and is provided at one end side (left end side) of the circular belt 122 in the rotation axis direction, and is composed of a base portion 163 and a belt insertion portion 164, and the belt insertion portion 164 is inserted inside the other end portion of the circular belt 122 and abuts against the inner surface of the circular belt 122.

[0055] 7, a sliding ring 160 is provided between one surface 163s of the base portion 163 of the support 161 and a belt end surface 122s on the other end side in the rotation axis direction of the circular belt 122. The sliding ring 160 is inserted into a belt insertion portion 164 of the support 161 and is held by the support 161 so as to be rotatable.

[0056] 7, a sliding ring 160 is provided on the support 162 side between the base 163 and the circular belt 122, similar to the support 161 side. The sliding ring 160 is inserted into a belt insertion portion 164 of the support 162, and is held by the support 162 so as to be rotatable.

[0057] Furthermore, the distance between one surface 163s of the base 163 of the support 161 and one surface 163s of the base 163 of the support 162 is more than twice the thickness of the sliding ring 160 and is greater than the length of the circular belt 122 in the Y-axis direction (rotation axis direction).

[0058] [2-9. Sliding ring] 7 and 10 showing the sliding ring 160 viewed from the Y-axis direction, the sliding ring 160 is a circular plate-shaped member with an outer diameter larger than that of the circular belt 122 and an inner diameter approximately equal to that of the belt insertion portion 164. In other words, the sliding ring 160 has a length T1, which is the difference between the outer diameter and the inner diameter, larger than a length T2 (see FIG. 8), which is the difference between the outer diameter and the inner diameter of the circular belt 122.

[0059] As described above, the sliding ring 160 is inserted into the belt insertion portion 164 of the supports 161 and 162 so as to be sandwiched between the belt end surface 122s of the circular belt 122 and the base portion 163 of the supports 161 and 162. Therefore, the rotation center of the sliding ring 160 and the rotation center of the circular belt 122 coincide with each other. That is, the sliding ring 160 is rotatable about the width direction (Y-axis direction) of the circular belt 122 as the rotation axis direction. As shown in FIG. 7, the sliding ring 160 is annular plate-shaped, so that the lower end portion protrudes downward (toward the pressure unit 130) from the lower ends of the C-shaped plate-shaped supports 161 and 162 and the nip portion 150.

[0060] The sliding ring 160 is provided for the purpose of preventing the belt end surface 122s of the circular belt 122 from sliding against one surface 163s of the base 163 of the supports 161, 162 when the circular belt 122 rotates, thereby preventing the belt end surface 122s and the base 163 from being worn down.

[0061] This sliding ring 160 is formed from a heat-resistant resin (such as PEEK (polyether ether ketone)) and may be coated on both sides or one side of its thickness with a material that has good sliding properties, such as PTFE (polytetrafluoroethylene).

[0062] [2-10. Pressurizing section] As shown in FIG. 3, the pressure unit 130 is specifically a pressure roller 131. The pressure roller 131 is a roller extending in the Y-axis direction. The pressure roller 131 is rotatable about a rotation axis J extending in the Y-axis direction by a driving source such as a motor (not shown). In other words, the pressure roller 131 is rotatable with the width direction of the pressure roller 131 as the rotation axis direction. As described above, the pressure roller 131 is pressed against the heater 121 with the heat diffusion member 125 and the circular belt 122 sandwiched therebetween, thereby forming the nip portion 150. The dotted arrow L1 shown in FIG. 3 indicates the transport path of the medium M in the fixing unit 30.

[0063] As shown in the cross section seen from one end in the longitudinal direction in Figure 11, the pressure roller 131 is a covered roller in which an elastic layer 133 of silicone rubber, a primer layer 134, and a surface layer 135 such as a PFA tube are layered in this order on the surface of a core metal 132, which is a cylindrical shaft made of free-cutting steel (SUM) or the like.

[0064] A non-conductive RTV silicone rubber having a thickness of 5 μm or less was used for the primer layer 134. A non-conductive PFA tube having a thickness of 15 to 25 μm was used for the surface layer 135. Furthermore, the elastic layer 133 had a thickness of 3 mm, and the pressure roller 131 had an overall outer diameter of φ30.

[0065] When this pressure roller 131 is pressed against the outer peripheral surface of the circular belt 122, the cylindrical laminated portion 136 consisting of the surface layer 135, the primer layer 134 and the elastic layer 133 contracts and deforms due to being pressed against the circular belt 122, forming a nip portion 150 at the point of contact with the circular belt 122.

[0066] As shown in FIG. 7, in the pressure roller 131, the metal core 132 is longer in the rotation axis direction than the laminated portion 136, and the metal core 132 protrudes outward in the rotation axis direction from the roller end faces 136s at both ends of the laminated portion 136.

[0067] Furthermore, the pressure roller 131 is arranged so that the length of the stacked portion 136 in the Y-axis direction (rotation axis direction) is shorter than the length of the circular belt 122 in the Y-axis direction, and both ends of the stacked portion 136 are positioned between both ends of the circular belt 122.

[0068] Furthermore, the core metal 132 of the pressure roller 131 is provided with a lubricant recovery member 170 (170A, 170B) that comes into contact with the sliding ring 160 at a portion that is outside the roller end faces 136s at both ends of the laminated portion 136 in the rotational axis direction and that faces the sliding ring 160 provided on the heating portion 120 side.

[0069] [2-11. Lubricant recovery parts] As shown in FIG. 7 and FIG. 12(A) showing the lubricant recovery member 170 (170A, 170B) from the Y-axis direction, and FIG. 12(B) showing the lubricant recovery member 170 (170A, 170B) from the X-axis direction, the lubricant recovery member 170 (170A, 170B) is a circular ring-shaped elastic member, more specifically, an elastic member having a hollow truncated cone shape (trumpet shape) like a bottomless hollow cone with the apex side cut off, and is attached to both ends of the core metal 132 of the pressure roller 131.

[0070] The lubricant recovery members 170 (170A, 170B) have an inner diameter on the small diameter side that is approximately the same as the outer diameter of the core metal 132, and are adapted to be inserted into the core metal 132. Specifically, as shown in Fig. 7, two lubricant recovery members 170 (170A, 170B) are inserted into the other end (right end) of the core metal 132 with their large diameter sides facing each other. Of the two lubricant recovery members 170, the lubricant recovery member 170 located on the inner side in the rotational axis direction of the core metal 132 is referred to as lubricant recovery member 170A, and the lubricant recovery member 170 located on the outer side in the rotational axis direction of the core metal 132 is referred to as lubricant recovery member 170B.

[0071] The two lubricant recovery members 170A, 170B sandwich a part (lower end portion) of the sliding ring 160 provided on the other end side of the heating unit 120 between the upper end portion of the large diameter side of the lubricant recovery member 170A and the upper end portion of the large diameter side of the lubricant recovery member 170B, and are fixed to the other end side of the core metal 132 by a fixing member (not shown) in a state in which they are elastically deformed so as to apply a force toward the sliding ring 160. In other words, the two lubricant recovery members 170A, 170B are arranged with their large diameter sides facing each other, and are abutted against each other so as to be pressed against each other and elastically deformed to form a nip portion, and are fixed to the other end side of the core metal 132 in a state in which a part (lower end portion) of the sliding ring 160 is sandwiched in the nip portion.

[0072] As a result, the upper end portion of the large diameter side of the lubricant recovery member 170A comes into contact with a portion (lower end portion) of the surface on the inner side (the circular belt 122 side) of the sliding ring 160, and the upper end portion of the large diameter side of the lubricant recovery member 170B comes into contact with a portion (lower end portion) of the surface on the outer side (the base 163 side) of the sliding ring 160. Similarly, at one end side of the core metal 132, the two lubricant recovery members 170A, 170B are fixed in an elastically deformed state so that a force is applied toward the sliding ring 160 sandwiched therebetween.

[0073] In addition, since the lubricant recovery members 170A and 170B are fixed to the core metal 132 with a part of the sliding ring 160 sandwiched in the nip portion, the position of the sliding ring 160 in the Y-axis direction is determined by the position of the nip portion of the lubricant recovery members 170A and 170B in the Y-axis direction. If the nip portion of the lubricant recovery members 170A and 170B is disposed in a position where the sliding ring 160 is pressed against the circular belt 122, the rotation of the circular belt 122 may be hindered or the end portion of the circular belt 122 may be damaged. For this reason, it is preferable to dispose the nip portion of the lubricant recovery members 170A and 170B in a position where the sliding ring 160 abuts against one surface 163s of the base portion 163 of the supports 161 and 162.

[0074] The lubricant recovery member 170 (170A, 170B) is formed of a resin such as PEEK, a film such as polyimide, an elastic material such as silicone rubber, etc. Note that, although details will be described later, the lubricant recovery member 170 (170A, 170B) is a member for recovering the lubricant 126 that has leaked out from the end of the circular belt 122 in the rotation axis direction to the outside of the circular belt 122 and adhered to the inner surface of the sliding ring 160.

[0075] [2-12.Other] The fixing unit 30 may include one or more other arbitrary components in addition to the above-mentioned components. The other components referred to here are, for example, a control unit that controls the operation of the fixing unit 30. The control unit includes, for example, a temperature adjustment circuit that controls the temperature of the heater 121 via the temperature sensor 123, and a power supply circuit that supplies current to the heater 121.

[0076] Here, the positional relationship between the pressure roller 131, the sliding ring 160, and the lubricant recovery member 170 of the fixing unit 30 will be described with reference to Fig. 13. Fig. 13 is a diagram of the pressure roller 131, the sliding ring 160, and the lubricant recovery member 170 as viewed from the Y-axis direction, and members other than the pressure roller 131, the sliding ring 160, and the lubricant recovery member 170 are omitted. The lubricant recovery member 170 shown in Fig. 13 is in an elastically deformed state such that a force is applied toward the sliding ring 160 sandwiched therebetween.

[0077] 13, the rotation center position of pressure roller 131 (i.e., the rotation center position of core metal 132) is set as the origin O in the Z-axis direction. Dotted line G shown in Fig. 13 is a line that passes through origin O and is parallel to the X-axis direction and nip portion 150 (see Fig. 3), and this dotted line G is set as the reference line. Position Q shown in Fig. 13 is the rotation center position of circular belt 122 and sliding ring 160.

[0078] Dotted line I is a line separated by a distance C from dotted line G, and indicates the inner diameter position of the sliding ring 160. In other words, the inner diameter position of the sliding ring 160 is separated by the distance C from the rotation center position (origin O) of the pressure roller 131.

[0079] Dotted line K is a line spaced a distance B from dotted line G, and indicates the outer diameter position of the lubricant recovery member 170. In other words, the outer diameter position of the lubricant recovery member 170 is spaced a distance B from the rotation center position (origin O) of the pressure roller 131.

[0080] Dotted line L is a line spaced a distance A from dotted line G, and indicates the position of nip portion 150. In other words, the position of nip portion 150 is spaced a distance A from the rotation center position (origin O) of pressure roller 131.

[0081] The lubricant recovery member 170 is a member intended to recover the lubricant 126 adhering to the sliding ring 160. For this reason, the outer diameter position of the lubricant recovery member 170 must be farther from the rotation center position (origin O) of the pressure roller 131 than the inner diameter position of the sliding ring 160. Therefore, the distance B from the origin O to the outer diameter position of the lubricant recovery member 170 is greater than the distance C from the origin O to the inner diameter position of the sliding ring 160.

[0082] On the other hand, if the lubricant recovery member 170 reaches the circular belt 122, there is a possibility that the circular belt 122 may be damaged. For this reason, the outer diameter position of the lubricant recovery member 170 must be closer to the rotation center position (origin O) of the pressure roller 131 than the position of the nip portion 150. Therefore, the distance B from the origin O to the outer diameter position of the lubricant recovery member 170 is smaller than the distance A from the origin O to the position of the nip portion 150.

[0083] From the above, the pressure roller 131, the sliding ring 160, and the lubricant recovery member 170 are disposed so that distance A>distance B>distance C when viewed from the Y-axis direction (rotation axis direction).

[0084] 7, the sliding ring 160 is provided between the belt end surface 122s of the circular belt 122 and one surface 163s of the base portion 163 of the supports 161 and 162 (support 162 is omitted in FIG. 7), and is sandwiched between the lubricant recovery members 170A and 170B. If the positions of the lubricant recovery members 170A and 170B in the Y-axis direction are too close to the stacked portion 136 of the pressure roller 131, the sliding ring 160 is pressed against the belt end surface 122s by the lubricant recovery members 170A and 170B, and the circular belt 122 may be damaged.

[0085] For this reason, as described above, it is desirable that the lubricant recovery members 170A and 170B are positioned in the Y-axis direction so that the sandwiched sliding ring 160 comes into contact with one surface 163s of the base portion 163.

[0086] 13, the lubricant recovery member 170A is fixed to the core metal 132 so that the length T3 in the Z-axis direction (radial direction of the lubricant recovery member 170A) of the nip portion that contacts the inner surface of the sliding ring 160 (the circular belt 122 side) is greater than the length T1 (i.e., the distance from the inner circumference to the outer circumference) which is the difference between the outer diameter and the inner diameter of the sliding ring 160. As a result, the lubricant recovery member 170A contacts the inner surface of the sliding ring 160 from the outer circumference side to the inner circumference side, so that the lubricant 126 attached to the inner surface of the sliding ring 160 and the lubricant reservoir 175 (see FIG. 14) described later can be reliably recovered. This concludes the description of the configuration of the fixing unit 30.

[0087] [3. Operation of image forming device] Next, the operation of the image forming apparatus 200 will be described in order of the overall operation of the image forming apparatus 200, the operation of the fixing unit 30, and the movement of the lubricant 126. First, the overall operation of the image forming apparatus 200 will be described.

[0088] When forming an image on medium M, image forming apparatus 200 sequentially performs a developing process, a transfer process, and a fixing process. That is, image forming apparatus 200 first sends out medium M stored in tray T using pickup roller 41, and then guides medium M from transport path R1 to transport path R2.

[0089] Here, in the developing process, the image forming apparatus 200 forms an electrostatic latent image on the surface of the photoconductor drum 13 of the developing unit 10, and then develops the electrostatic latent image by attaching toner to the electrostatic latent image, thereby forming a toner image.

[0090] Next, as a transfer process, the image forming apparatus 200 transfers the toner image formed on the surface of the photosensitive drum 13 to the medium M by the transfer unit 20. Finally, as a fixing process, the image forming apparatus 200 fixes the toner image transferred to the medium M to the medium M by applying heat and pressure by the fixing unit 30. This results in an image being formed (i.e., printed) on the medium M. The medium M on which the image has been formed in this way is discharged into the stacker 2 of the image forming apparatus 200. The overall operation of the image forming apparatus 200 is as described above.

[0091] Next, the operation of the fixing unit 30 will be described in detail. When the medium M is heated, the fixing unit 30 moves the heating section 120 so as to approach the pressure section 130. At this time, the pressure roller 131 is pressed against the circular belt 122 to form the nip section 150. Here, in the fixing unit 30, the medium M is supplied to the upstream side of the nip section 150 in the belt rotation direction (the right side in the figure) along the conveying path shown by the dotted arrow L1 in FIG. 3. At this time, the fixing unit 30 conveys the medium M supplied to the upstream side of the nip section 150 in the belt rotation direction to the downstream side of the nip section 150 in the belt rotation direction by rotating the circular belt 122 in the belt rotation direction shown by the arrow D in conjunction with the rotation of the pressure roller 131. At this time, in the fixing unit 30, the heat generated by the heater 121 is conducted to the circular belt 122 via the heat diffusion member 125, so that the circular belt 122 is heated. As a result, the medium M passing through the nip portion 150 (i.e., between the circular belt 122 and the pressure roller 131) is heated while being pressurized, and at this time, the toner image is fixed onto the medium M. The details of the operation of the fixing unit 30 are as described above.

[0092] Next, the movement of the lubricant 126 in the fixing unit 30 will be described with reference to Figures 3, 4, and 14. Note that Figure 14 is a view of the sliding ring 160, the belt insertion portion 164, and the lubricant recovery member 170A provided on the other end side of the fixing unit 30 in the Y-axis direction as viewed from the Y-axis direction, and members other than the sliding ring 160, the belt insertion portion 164, and the lubricant recovery member 170A are omitted.

[0093] When assembling the heating unit 120, the lubricant 126 is applied to the application area 141 (FIG. 6) of the heat diffusion member 125. The lubricant 126 applied to the application area 141 is sandwiched and crushed between the heat diffusion member 125 and the circular belt 122. After that, when the power of the image forming apparatus 200 is turned on, the pressure roller 131 is rotated in the roller rotation direction indicated by the arrow E in FIG. 3 by a driving source (not shown). At this time, the circular belt 122 rotates together with the pressure roller 131 in the belt rotation direction indicated by the arrow D.

[0094] When the circular belt 122 rotates, the lubricant 126 attached to the inner peripheral surface of the circular belt 122 moves in the directions indicated by the arrows D1, D2, and D3, and is carried to the edge portion 151 located on the upstream side of the support body 127 in the belt rotation direction. A part of the lubricant 126 carried to the edge portion 151 is scraped off by the edge portion 151 without entering between the heat diffusion member 125 and the circular belt 122.

[0095] In this way, each time the circular belt 122 rotates, a portion of the lubricant 126 is scraped off by the edge portion 151, so that the lubricant 126 accumulates on the upstream side of the edge portion 151 in the belt rotation direction (upper side in the figure) as shown in FIG.

[0096] The movement of the lubricant 126 thereafter will be described separately for the case where the lubricant recovery member 170 is omitted and the case where the lubricant recovery member 170 is provided. First, as a comparison with this embodiment, the movement of the lubricant 126 when the lubricant recovery member 170 is omitted will be described with reference to Fig. 15. Fig. 15 is a cross-sectional view of a portion of the heating unit 120 (specifically, the other end side portion in the Y-axis direction), and shows the cross section as seen from one end side (lower side) in the Z-axis direction.

[0097] As described above, when the circular belt 122 rotates, a part of the lubricant 126 is scraped off by the edge portion 151, so that the lubricant 126 accumulates on the upstream side of the edge portion 151 in the belt rotation direction as shown in FIG.

[0098] Thereafter, the amount of the lubricant 126 gradually increases with the rotation of the circular belt 122, and is carried in a manner of being pushed out from the center side of the rotation axis direction (Y axis direction) of the circular belt 122 toward the other end side of the rotation axis direction (direction indicated by arrow F1) on the belt rotation direction upstream side of the edge portion 151 (upper side in FIG. 15). The lubricant 126 carried to the other end of the rotation axis direction of the circular belt 122 reaches the sliding ring 160 and adheres to the sliding ring 160, moves along the sliding ring 160 in the direction of arrow F2, and leaks out from a gap between the belt end surface 122s of the circular belt 122 and the sliding ring 160 in the direction of arrow F3 (i.e., outside the circular belt 122).

[0099] The lubricant 126 leaked out in this manner forms a lubricant pool 175 on the inner surface of the sliding ring 160 (on the circular belt 122 side).

[0100] If the lubricant 126 continues to leak out of the circular belt 122, the lubricant pool 175 grows and adheres to the other end of the circular belt 122 in the rotation axis direction. If the lubricant 126 continues to leak out, the area of ​​adhesion of the lubricant 126 gradually expands from the other end of the rotation axis direction to the center of the rotation axis direction on the outer peripheral surface of the circular belt 122. In this way, if the lubricant recovery member 170 is omitted, the lubricant 126 leaking from the end of the circular belt 122 in the rotation axis direction adheres to the outer peripheral surface of the circular belt 122 via the sliding ring 160, and the transfer of heat from the circular belt 122 to the image on the medium M when fixing the image on the medium M becomes insufficient, which may cause printing defects.

[0101] In contrast, the movement of the lubricant 126 when the lubricant recovery member 170 according to this embodiment is provided will be described with reference to Fig. 14. Even when the lubricant recovery member 170 is provided, the lubricant 126 reaches the sliding ring 160 and adheres to the sliding ring 160, leaks out from the gap between the circular belt 122 and the sliding ring 160, and a lubricant reservoir 175 is formed on the inner surface of the sliding ring 160 (on the circular belt 122 side).

[0102] Here, the lubricant recovery member 170 forms a nip portion by elastically deforming two opposing lubricant recovery members 170A, 170B that are pressed against each other, and is fixed to the core metal 132 with a part of the sliding ring 160 sandwiched in the nip portion. For this reason, when the pressure roller 131 rotates, the lubricant recovery members 170A, 170B also rotate accordingly, and the sliding ring 160 sandwiched in the nip portion between the lubricant recovery members 170A, 170B also rotates.

[0103] As a result, the lubricant 126 (omitted in Figure 14) adhering to the inner surface of the sliding ring 160 and the lubricant reservoir 175 are transported in the directions of arrows F4 and F5 (i.e., the rotational direction of the sliding ring 160) as the sliding ring 160 rotates, and reach the recovery point P where the sliding ring 160 is sandwiched in the nip portion of the lubricant recovery members 170A and 170B.

[0104] When the lubricant 126 and the lubricant reservoir 175 adhering to the sliding ring 160 reach the recovery point P, they are removed (recovered) from the sliding ring 160 onto the lubricant recovery member 170A. In this way, the lubricant 126 and the lubricant reservoir 175 removed onto the lubricant recovery member 170A move in the direction of the arrow F6 (i.e., the rotation direction of the lubricant recovery member 170A) as the lubricant recovery member 170A rotates, but since they remain on the lubricant recovery member 170A, they do not return to the sliding ring 160 again.

[0105] In this manner, in the present embodiment, the lubricant 126 on the sliding ring 160 can be recovered from the sliding ring 160 by the lubricant recovery member 170 (170A, 170B) before it grows into a lubricant reservoir 175. This prevents the lubricant 126 leaking from the end of the circular belt 122 in the rotational axis direction from adhering to the outer peripheral surface of the circular belt 122 via the sliding ring 160, thereby preventing printing defects from occurring.

[0106] 14 and 15, the movement of the lubricant 126 at the other end side of the fixing unit 30 in the Y axis direction is described, but the movement of the lubricant 126 at one end side of the fixing unit 30 in the Y axis direction is similar.

[0107] [4. Summary and Effects] As described above, in this embodiment, the fixing unit 30 as a fixing device is provided with the circular belt 122, which is an example of a cylindrical fixing member having a lubricant 126 on its inner surface and rotatable with the longitudinal direction (Y-axis direction) as the rotational axis direction, the sliding ring 160 arranged opposite the widthwise end, which is the longitudinal side end, of the circular belt 122, the pressure roller 131, which is an example of a pressure member provided opposite the outer peripheral surface of the circular belt 122 and abuts against the outer peripheral surface of the circular belt 122 to form a nip portion 150 between the circular belt 122, and the lubricant recovery member 170, which is an example of a contact member arranged at the widthwise end, which is the longitudinal side end, of the pressure roller 131 (Y-axis direction and rotational axis direction), and which comes into contact with the sliding ring 160.

[0108] More specifically, a lubricant recovery member 170A as an example of a first contact member and a lubricant recovery member 170B as an example of a second contact member are provided at one end in the rotation axis direction of a core metal 132 as an example of a shaft serving as a rotation axis of the pressure roller 131, facing each other in the longitudinal direction (Y-axis direction, rotation axis direction) of the pressure roller 131 and in contact with each other so as to be pressed against each other. Then, the sliding ring 160 is sandwiched between the lubricant recovery member 170A and the lubricant recovery member 170B, and the lubricant recovery member 170A is in contact with a part (lower end portion) of the surface of the sliding ring 160 on the circular belt 122 side. Similarly, lubricant recovery member 170A and lubricant recovery member 170B are provided on the other end side in the rotational axis direction of core metal 132 of pressure roller 131, and sliding ring 160 is sandwiched between lubricant recovery member 170A and lubricant recovery member 170B so that lubricant recovery member 170A contacts a portion of the surface of sliding ring 160 facing circular belt 122.

[0109] In this way, in the fixing unit 30 of this embodiment, the lubricant 126 and the lubricant reservoir 175 that have leaked out from the end of the circular belt 122 in the rotation axis direction and adhered to the surface of the sliding ring 160 on the circular belt 122 side can be collected (removed) by the lubricant recovery member 170A that comes into contact with the surface of the sliding ring 160 on the circular belt 122 side, so that it is possible to prevent the lubricant 126 that has leaked out from the end of the circular belt 122 in the rotation axis direction from adhering to the outer circumferential surface of the circular belt 122 via the sliding ring 160. Thus, the fixing unit 30 of this embodiment can prevent the occurrence of printing defects.

[0110] Furthermore, since fixing unit 30 employs a direct heating method in which nip portion 150 is directly heated by heat generated by heater 121, lubricant 126 is softened by heat and tends to move, which tends to cause lubricant pool 175. For this reason, in a fixing device employing a direct heating method like fixing unit 30, recovery of lubricant 126 by lubricant recovery members 170A and 170B is particularly effective.

[0111] Furthermore, in the fixing unit 30, the sliding ring 160 is rotatable with the longitudinal direction (Y-axis direction and width direction) of the circular belt 122 as the axis of rotation, and the lubricant recovery member 170A and the lubricant recovery member 170B inserted into the ends of the core metal 132 come into contact with each other and elastically deform, forming a nip portion, and with a portion (lower end portion) of the sliding ring 160 sandwiched in the nip portion, the sliding ring 160 rotates in conjunction with the rotation of the pressure roller 131, thereby rotating the sliding ring 160 sandwiched in the nip portion.

[0112] In this way, in the fixing unit 30, the lubricant 126 and the lubricant reservoir 175 adhering to the sliding ring 160 can be transported to the nip portion where the lubricant recovery member 170A, the lubricant recovery member 170B, and the sliding ring 160 come into contact with each other, and can be recovered by the lubricant recovery member 170A.

[0113] Furthermore, by rotating the sliding ring 160 using the lubricant recovery member 170A and the lubricant recovery member 170B in this manner, even when the sliding ring 160 comes into contact with the circular belt 122, the contact point is not biased, so that uneven wear of the sliding ring 160 can be suppressed.

[0114] 5. Other embodiments [5-1. Another embodiment 1] In the above-described embodiment, a lubricant recovery member 170A, which is an example of a first contact member located on the inside in the rotational axis direction of the pressure roller 131, and a lubricant recovery member 170B, which is an example of a second contact member located on the outside in the rotational axis direction, are fixed to one end side and the other end side of the core wire 132 in a deformed state so as to be pressed against each other.

[0115] 16, instead of the lubricant recovery member 170B located on the outer side in the rotational axis direction of the pressure roller 131, a lubricant recovery member 300 that is a hard member in the shape of a circular ring and does not elastically deform may be provided as the second contact member. In this case, since the position of the inner surface of the lubricant recovery member 300 is the position of the nip portion, the position of the nip portion can be easily fixed compared to the case where the lubricant recovery member 170A and the lubricant recovery member 170B that deform relative to each other are provided, and therefore, the sliding ring 160 can be easily fixed at a desired position (specifically, the position where it contacts the base 163 of the supports 161, 162).

[0116] Alternatively, the present invention is not limited to this, and for example, the lubricant recovery member 170B located on the outer side in the rotation axis direction of the pressure roller 131 may be omitted, and only the lubricant recovery member 170A located on the inner side may be provided.

[0117] In addition, the present invention is not limited to this, and for example, instead of the lubricant recovery members 170A and 170B, a blade-shaped lubricant recovery member (not shown) may be provided that is fixed to a frame (not shown) of the fixing unit 30, not to the core metal 132 of the pressure roller 131, and that comes into contact with the sliding ring 160. In this case, similar to the lubricant recovery members 170A and 170B, the sliding ring 160 may be sandwiched between two blade-shaped lubricant recovery members in the rotation axis direction, or one blade-shaped lubricant recovery member may be brought into contact with one surface of the sliding ring 160 on the side of the circular belt 122. The shapes of the lubricant recovery members 170A and 170B and the materials forming them described in the above-mentioned embodiment are merely examples, and other shapes and materials may be adopted.

[0118] [5-2. Other embodiment 2] In the above-described embodiment, the lubricant recovery members 170A, 170B are made of an elastic material, but they may be made of a rigid material that does not elastically deform. In addition, the present invention is not limited to this. For example, the surfaces of the lubricant recovery members 170A, 170B may be formed with fine irregularities to make it easier for the lubricant 126 to adhere to the lubricant recovery members 170A, 170B, or the lubricant recovery members 170A, 170B may be made of a porous material such as a sponge to allow the lubricant recovery members 170A, 170B to absorb the lubricant 126.

[0119] [5-3. Other embodiment 3] Furthermore, in the above-described embodiment, the lubricant 126 and the lubricant reservoir 175 adhering to the sliding ring 160 are collected by the lubricant recovery member 170A. Here, the lubricant 126 and the lubricant reservoir 175 collected by the lubricant recovery member 170A may fall downward from the lubricant recovery member 170A. For this reason, a recovery box (not shown) for storing the lubricant 126 and the lubricant reservoir 175 that have fallen from the lubricant recovery member 170A may be provided below the lubricant recovery member 170A.

[0120] In this case, the lubricant recovery members 170A and 170B may be formed of a fluororesin such as PFA (perfluoroalkoxyalkane) that makes the lubricant 126 and the lubricant reservoir 175 slippery. In this way, the lubricant 126 and the lubricant reservoir 175 recovered by the lubricant recovery member 170A can easily drop from the lubricant recovery member 170A into a recovery box below.

[0121] [5-4. Other embodiment 4] Furthermore, in the above-described embodiment, the sliding rings 160 are provided on both ends of the circular belt 122 in the axial direction, and the lubricant recovery members 170 (170A, 170B) are provided on both ends of the circular belt 122 in the axial direction. However, the present invention is not limited to this. For example, in a configuration in which the circular belt 122 is closer to one of the ends in the axial direction and the lubricant 126 leaks out only from the one end, the sliding ring 160 may be provided only on one side of the circular belt 122 in the axial direction, and the lubricant recovery members 170 (170A, 170B) may be provided only on one side of the pressure roller 131 in the axial direction.

[0122] [5-5. Other embodiment 5] Furthermore, in the above-described embodiment, the present invention is applied to the image forming apparatus 200, but the present invention is not limited to this, and can be applied to various image forming apparatuses equipped with a fixing device such as the fixing unit 30 (that is, employing an electrophotographic method). For example, the present invention can be applied to image forming apparatuses equipped with a fixing device, such as a copier, a multifunction machine, and a fax machine.

[0123] [5-6. Other embodiment 6] Furthermore, the present invention is not limited to the above-described embodiments, and the scope of application of the present invention extends to embodiments in which some or all of the above-described embodiments are combined in any manner, or in which some of the embodiments are extracted. [Industrial Applicability]

[0124] The present invention can be widely used in, for example, electrophotographic printers. [Explanation of symbols]

[0125] 200: image forming apparatus, 30: fixing unit, 110: housing, 120: heating section, 130: pressure section, 140: connector, 121: heater, 122: circular belt, 123: temperature sensor, 124: thermally conductive plate, 125: thermal diffusion member, 126: lubricant, 127, 128, 161, 162: support, 129: compression spring, 131: pressure roller, 132: core metal, 136: stacking section, 150: nip section, 151, 152: edge section, 160: sliding ring, 170A, 170B, 300: lubricant recovery member, 175: lubricant reservoir, M: medium.

Claims

1. a fixing member having a lubricant on an inner circumferential surface thereof and rotatable about a rotation axis in a longitudinal direction; a sliding ring disposed opposite to a longitudinal side end of the fixing member; a pressure member provided opposite to an outer peripheral surface of the fixing member and abutting against the outer peripheral surface of the fixing member to form a nip portion between the fixing member and the pressure member; a contact member disposed at a side end of the pressing member in the longitudinal direction and contacting the sliding ring; Equipped A fixing device comprising:

2. The sliding ring is disposed on both sides or one side of the longitudinal end portion of the fixing member, The contact member is disposed on the side of the longitudinal end portion of the pressure member on which the sliding ring is disposed.

2. The fixing device according to claim 1,

3. The contact member is The sliding ring contacts a portion of the fixing member side.

3. The fixing device according to claim 1, wherein the fixing member is a fixing member having a fixing surface.

4. The pressure member is the pressure member is rotatable about a rotation axis along a longitudinal direction of the pressure member, and rotates in contact with an outer peripheral surface of the fixing member; The contact member is It is fixed to the end of the shaft that is the rotation axis of the pressure member, and rotates together with the shaft while being in contact with the sliding ring.

2. The fixing device according to claim 1,

5. The sliding ring is The fixing member is rotatable about a longitudinal direction of the fixing member as a rotation axis direction, The contact member is a first annular contact member that is inserted onto an end of the shaft and that comes into contact with a portion of the sliding ring on the side of the fixing member, and a second annular contact member that is inserted onto an end of the shaft and that comes into contact with a portion of the sliding ring on the side opposite to the fixing member, The first contact member and the second contact member are The shaft is fixed to the shaft with a part of the sliding ring sandwiched therebetween, and the sliding ring is rotated by rotating together with the shaft with a part of the sliding ring sandwiched therebetween.

5. The fixing device according to claim 4.

6. The first contact member and the second contact member are elastic members that are elastically deformable, and are pressed against each other to abut against each other and elastically deform to form a nip portion, and are fixed to the shaft with a portion of the sliding ring sandwiched in the nip portion.

6. The fixing device according to claim 5,

7. The first contact member and the second contact member each have a hollow truncated cone shape, and the large diameter sides of the first contact member and the second contact member are opposed to each other and pressed against each other to elastically deform, thereby forming the nip portion.

7. The fixing device according to claim 6,

8. the first contact member is an elastic member that is elastically deformable, the second contact member is a hard member that does not elastically deform, The first contact member and the second contact member are fixed to the shaft in a state where the first contact member is pressed against the second contact member and the first contact member is elastically deformed to form a nip portion, and a part of the sliding ring is sandwiched in the nip portion.

6. The fixing device according to claim 5,

9. the first contact member is a hollow truncated cone-shaped elastic member, the second contact member is a hard member having a circular ring shape, The first contact member and the second contact member come into contact with each other so as to press a large diameter side of the first contact member against the second contact member, and the first contact member is elastically deformed to form the nip portion. The fixing device according to claim 8 .

10. The first contact member includes: The radial length of the first contact member at the nip portion that contacts the portion of the sliding ring on the fixing member side is greater than the distance from the inner circumference to the outer circumference of the sliding ring, and the first contact member contacts the portion of the sliding ring on the fixing member side from the inner circumference to the outer circumference.

10. The fixing device according to claim 5, wherein the fixing member is a fixing member having a fixing surface.

11. The fixing device according to claim 1 is provided.

1. An image forming apparatus comprising:

Images